One of the three men who had plotted to blow up the New York City subway system in September of 2009 appeared in Brooklyn Federal Court Tuesday to testify in the trial of co-conspirator Adis Medunjanin.

Najibullah Zazi, who has pleaded guilty to his role in the bombing plot, told the court how he and his former Flushing High School classmates, Zarein Ahmedzay and Medunjanin, had traveled to Pakistan where they attended an Al Qaeda training camp in the summer of 2008.

Both Ahmedzay and Zazi have agreed to cooperate with the prosecution of Medunjanin, who continues to plead not guilty to charges of conspiring to use weapons of mass destruction and to commit murder abroad. Zazi's statements confirmed much of what Ahmedzay had said during his separate testimony on Monday, though Zazi included much more detail of the plot's inception.

The three friends, who had attended the same high school and mosque in Queens, had grown increasingly upset with America's military presence in the Middle East following the 9/11 attacks, which they believed America had brought upon itself. The trio then decided to travel to Afghanistan via Pakistan where they planned to fight American Troops.

Once they reached Pakistan, however, the men were offered an opportunity to spend time at an Al Qaeda training camp where they learned how to use deadly weapons and to construct bombs from house hold chemicals such as nail polish remover.

Zazi further explained how they met with a top Al Qaeda operative called Hamad, who authorities believe to be Adnan Shukrijumah, a wanted criminal who has plotted attacks for Al Qaeda worldwide. Hamad convinced the men to take advantage of their American citizenship and to plan an attack on American soil.

We started the conversation on such targets as Walmart, the stock exchange, Times Square, movie theaters and buses, Zazi said, but they ended up choosing the subway because it's the heart of everything in New York City.

The plan was hatched and the three agreed to detonate backpack bombs at three different subway locations during morning rush hour.

Medunjanin's defense lawyer, Robert C. Gottlieb, maintained his client's innocence during opening statements and claimed that Medunjanin had a falling out with his friends and had pulled out of the plot early on. However, would-be-shoe bomber Saajid Muhammad Badat, who is facing charges in Britain, agreed yesterday to testify against Medunjanin in exchange for a two-year reduction from his 13-year prison sentence.